1. Field of the Invention
The invention relates to an air intake apparatus mounted to an internal combustion engine. More particularly, the invention relates to an air intake apparatus configured to combine air that has been filtered separately by a plurality of air cleaners and lead that air to a single intake throttle valve.
2. Description of the Related Art
An air intake apparatus is typically mounted to a cylinder head of an internal combustion engine mounted in a vehicle, for example, via an intake manifold.
One such air intake apparatus which is disclosed in Japanese Utility Model Publication No. 58-84362U, for example, is a twin air intake apparatus configured such that air which has been drawn in separately from, for example, two air cleaner inlets and filtered separately by two air cleaners is led to a throttle body which serves as a single intake throttle valve. In this case, the intake ducts for the two air cleaners are arranged apart from one another in the vehicle width direction.
Because the intake ducts for the two air cleaners are arranged separated from one another in the vehicle width direction, however, wind produced as the vehicle runs is not always drawn in evenly to the two intake ducts with this related air intake apparatus.
As a result, the pressures of the airflows introduced into the throttle body separately from the two air cleaners tends to vary depending on the running state of the vehicle. Moreover, a phenomenon may occur in which the outputs of each of the two airflow meters separately arranged from the two air cleaners to the single intake throttle valve fluctuate or vary due to a disturbance in airflow which has no place to go when the intake throttle valve is temporarily closed.
Such variation in the outputs of the airflow meters leads to reduced accuracy in air-fuel ratio control that uses the output of the airflow meter, so there still remains room for improvement.